1. Field of the Invention
The invention relates to a method of controlling radio resources in telecommunications system, an arrangement, and a radio network controller.
2. Description of the Related Art
Controlling the transmit power of radio channels plays a significant role in the performance of interference limited telecommunications systems, such as CDMA (Code Division Multiple Access) systems. As the performance requirements have increased, the power control is required to account for fast temporal changes in the radio channels.
One tool for providing a fast power control is based on closed-loop power control, wherein a receiver receives a dedicated channel and performs a SIR (Signal-to-Interference Ratio) measurement on the dedicated channel. A transmit power control command is generated based on a comparison between a target SIR and the SIR measurement, and the transmit power control command is transmitted to the transmitter in order to adjust the transmit power of the dedicated channel to provide the target SIR. The target SIR is typically generated on the basis of success or failure of decoding a coding block, such as a frame, within limits of required quality, such as that defined by a FER target.
Some telecommunications systems support rate control, which enables changing the data rate in a time scale of the order of the duration of data coding block.
Therefore it is desired to consider power control methods, which account for the rate control.